Been trying to figure this out for a month. All started with the bottom carb. leaking a small amount of fuel and the motor was slightly missing. Not missing badly enough to worry me. Had a mechanic take it apart, clean it out, fix the leak and put it back together. Got it back, no more gas leaking, took it to the lake and the motor ran alot worse. It would idle pretty smoothly, but as soon as I mash on the gas, it starts missing. But once I get to 3/4 of a throttle, it's smooths out some with a small miss here and there, and I'm doing about 34mph at that. Mash the throttle down all the way from there and it starts missing more and wont pick up anymore speed than 34mph. When the motor is running normal, I usually get the boat running in the mid 40s wide open.
Figured this definatly had something to do with the carburetor since that was the only thing that was messed with. Had a buddy come out and we pulled the carbs off and took them apart. Cleaned them out, snychrinized the floats. Only thing was that the needle in bottom carb had a small crack, replaced that. Put them back on and ran to the lake, motor still ran bad.
Checked compression, checked out good on all cyl. Took a look at the fire, cyl # 2 was only firing sometimes. 2nd wire on trigger wasn't giving off voltage, replaced it and checked fire again... 2nd cyl. was still only firing every once in a while. Another mechanic in town let me borrow a set of coil packs, stator and regulator. Cyl 2 is now firing just fine all the time, but motor is running no different.
Put new spark plugs in and ran the boat, got back and checked the plugs and found water. Turns out there was alot of water in my gas tank. Sucked all the gas out, put half a bottle of seafoam and fresh 100% gas in the tank and ran it. Motor still missed quite a bit coming out of the hole but ran alot smoother wide open and motor trimmed up. But still at a loss of speed.
My powerhead gasket appears to be blown, the gasket at the bottom of the powerhead. Water is spitting out from there into the bottom of the cowl, I am told this is excess water from the water pump that meets with the exhaust and is blown out of the back of the motor and should'nt be causing it to miss. We also checked the plugs with this going on and after I had taken the bad gas out, and no water was showing up on plugs. I'm obviously going to replace the gasket soon, but I'm curious to see if any of you think this could be the problem?
If the timing gun is right, the timing on the motor is reading 10 millemeters on the low side and 30 millemeters on the high side. Should be 3 on low and 20 on high. Again, not sure if that could cause the motor to run like it is.
The only other thing that I haven't done is adjust the air/gas mixture screws on the carbs after adjusting the floats. (I'm waiting to have someone do it that knows what to do)
All the fuel lines are tight and secure, fuel pump is good, rebuilt it a few months ago and checked it again to be sure. Also, the motor is turning 55-5600 RPMs as it always has.
That should be all the info I have on what's going on with this motor and what we have done to it. My brain is about fried but I'm set on getting it running good again!! LOL
Figured this definatly had something to do with the carburetor since that was the only thing that was messed with. Had a buddy come out and we pulled the carbs off and took them apart. Cleaned them out, snychrinized the floats. Only thing was that the needle in bottom carb had a small crack, replaced that. Put them back on and ran to the lake, motor still ran bad.
Checked compression, checked out good on all cyl. Took a look at the fire, cyl # 2 was only firing sometimes. 2nd wire on trigger wasn't giving off voltage, replaced it and checked fire again... 2nd cyl. was still only firing every once in a while. Another mechanic in town let me borrow a set of coil packs, stator and regulator. Cyl 2 is now firing just fine all the time, but motor is running no different.
Put new spark plugs in and ran the boat, got back and checked the plugs and found water. Turns out there was alot of water in my gas tank. Sucked all the gas out, put half a bottle of seafoam and fresh 100% gas in the tank and ran it. Motor still missed quite a bit coming out of the hole but ran alot smoother wide open and motor trimmed up. But still at a loss of speed.
My powerhead gasket appears to be blown, the gasket at the bottom of the powerhead. Water is spitting out from there into the bottom of the cowl, I am told this is excess water from the water pump that meets with the exhaust and is blown out of the back of the motor and should'nt be causing it to miss. We also checked the plugs with this going on and after I had taken the bad gas out, and no water was showing up on plugs. I'm obviously going to replace the gasket soon, but I'm curious to see if any of you think this could be the problem?
If the timing gun is right, the timing on the motor is reading 10 millemeters on the low side and 30 millemeters on the high side. Should be 3 on low and 20 on high. Again, not sure if that could cause the motor to run like it is.
The only other thing that I haven't done is adjust the air/gas mixture screws on the carbs after adjusting the floats. (I'm waiting to have someone do it that knows what to do)
All the fuel lines are tight and secure, fuel pump is good, rebuilt it a few months ago and checked it again to be sure. Also, the motor is turning 55-5600 RPMs as it always has.
That should be all the info I have on what's going on with this motor and what we have done to it. My brain is about fried but I'm set on getting it running good again!! LOL
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